This invention relates to valve control arrangements for internal combustion engines having a valve capable of deactivation.
PCT International Application No. WO 93/18284 discloses a valve control arrangement in which a cup tappet constitutes a coupling element between a camshaft and an intake or exhaust valve in a cylinder head which is capable of deactivation. In that arrangement, pistons which are radially displaceable by hydraulic pressure act as locking elements. The pistons are arranged so that, in a first position which causes the valve to be activated, they connect the valve in locked relation to the tappet and, in a second position in which the valve is deactivated, they permit relative displacement of the tappet with respect to the valve to provide an idle tappet stroke. To assure that the tappet remains in contact with the camshaft when the valve is deactivated, a spring is provided between the spring plate and the tappet in addition to the conventional valve-closing spring which acts on a spring plate affixed to the end of the valve stem.